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Dr. Steve Kass Department of Psychology University of West Florida. Military Psychology: Human Factors. What is Human Factors?.
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Dr. Steve KassDepartment of PsychologyUniversity of West Florida Military Psychology: Human Factors
What is Human Factors? • The discovery and application of information about human behavior, abilities, and other characteristics to the design of tools, machines, systems, tasks, jobs, and environments for productive, safe, comfortable, and effective human use.
Human Factors Psychology and Related Disciplines • Ergonomics • Human Factors Engineering • Engineering Psychology • Human-Machine Interaction • Cognitive Engineering • Industrial/Organizational Psychology
History of Human Factors • Emerged during World War II • Need for people to effectively operate sophisticated military systems • Early emphasis was on productivity and physiology • After WWII the discipline continued to grow to meet the challenge of non-military problems • Emphasis shifted to include other objectives, such as safer and healthier working environments and improvements in the quality of working life • HF boosted by space program, computers, home technology
Role of Human Factors • User-Centered Design • Systems designed to fit people (not vice-versa). • Reduces training time. • Minimizes human error. • Improves comfort, safety, and productivity.
HF Approaches to Problem-Solving • Equipment Design – change physical equipment • Task Design – change how task is accomplished • Environmental Design – change features of the work environment such as temperature, lighting, sound • Training – change worker behavior by providing skills and teaching procedures
Human Factors Military Activities • Accident Investigation • Simulation, Virtual Reality, & Training • Equipment/Task Design • Basic & Applied Research
Accident Investigation July 1988, USS Vincennes shot down Iranian civilian airliner killing 290 on board February 2001, USS Greeneville accidentally sinks Japanese fishing boat killing 9 crewmembers (4 HS students)
Military TrainingIntelligent Enemies (LG) • Intelligent Enemies • Courses of action (COA) not developed sequentially. • COA/eCOA assessed simultaneously by LG zones. • Hypergames • Strategic, operational and tactical considerations in one game. • Hyperlinked at different resolutions for continuous real-time play.
Displays used for Training Joint Combat Advanced Display and Debriefing System (JCADDS)
Environment • Heat/Cold • G-forces/Weightlessness • Altitude • Lighting • Noise/Vibration • Stress • Chemicals
Light & VisionDark Adaptation • Takes about 30 minutes to dark adapt, but just a few minutes to light adapt Human Factors application: Why use red lights in cockpits and darkrooms? - because rods are insensitive to longer wavelengths (red) the eyes “think” they are in the dark already allowing user to dark adapt more quickly)
Sense of Touch:Tactile and Haptic Tactile– Cutaneous or somatosensory sense provided by receptors just under the skin. Types of Receptors: Thermoreceptors– detect heat/cold Mechanoreceptors– detect pressure Nociceptors – detect noxious stimuli (causticsubstances) Haptic– Shape information provided through manipulation of fingers This device provides haptic information to aid in performing a tracking task. The user feels the button pop out and must move the stick in the same direction to maintain course. Human factors application of haptic research
Vestibular System Vestibular System – detects acceleration forces, maintains upright posture/balance and controls eye position relative to head Semicircular Canals – detect angular acceleration (rotation) in 3 axes - a crista embedded in a jelly-like material (cupola) is supported by hair cells that bend and fire when the crista moves in response to head rotation. Vestibular Sacs (Utricle & Saccule) – detect linear acceleration - hair cells embedded in jelly-like substance lag behind when the head moves. When motion becomes steady, otoliths catch up and hairs no longer bent.
Gz Gy Gx Acceleration High G-force tolerances • +/- 2 Gz – pressure on butt, drooping face, noticeable weight increase • +/- 3-4 Gz – Difficult to move, loss of fine motor movements, speech affected • + 5.5 Gz – Negative blood pressure -> GLOC or grayout (passengers may blackout sooner) • Higher tolerances (>10) possible in Gx plane (forward acc) – weight on chest, difficulty breathing Prevention/Protection • G-suit – squeezes blood out of extremities – increases tolerance by 2 G • Active Straining Maneuver (Blue Angels) – Pull head down, slow forceful breathing, tensing of muscles – increase tolerance by 1.5 G Note: force of gravity ~9.8 m/sec2 or 33 ft/sec2, therefore 5 G would be roughly equivalent to going from 0 to 112 mph in one sec
Motion Disturbances Spatial Disorientation – vestibular illusion which tricks the brain into thinking body is a different position than it actually is. Vection – the illusion of self-motion induced my visual cues Somatogravic Illusion – acceleration creates illusion that plane is nose-up, deceleration feels like the plane is nose-down Motion Sickness– nausea, disorientation and fatigue attributed to disturbance of vestibular system caused when vision and inner ear send conflicting (decoupled) signals • Treatments– • Medications – Antihistamines (Dramamine), Dopamine blockers or anti-psychotics (Thorazine), anti-nausea (serotonin) and Scopolamine (anticholinergic) • Behavioral strategies – sit facing front with front window view, eat bland foods such as bread, bananas, rice. If on a boat, stay in middle (less rocking) and look forward at the horizon, not at the waves.
Sopite Syndrome • Sopite Syndrome– motion induced drowsiness • Subset of motion sickness symptoms, but sometimes the sole manifestation • Dangerous because victims often not aware of its onset or the likelihood of onset • Found to affect passengers and operators of cars, trucks, ships, helicopters, planes, and simulators • No known prevention techniques (many motion sickness medications increase drowsiness) • May be a major cause of accidents and military pilot pilot training washout
Heat Stress • Small fluctuations in body temp greatly impact physical & cognitive performance • Problems include: • +/- 6° C of core body is fatal (normal ~ 37° C) • Dehydration, heat exhaustion, heat stroke • Effects on continuous, low arousal tasks (vigilance) • Aggravated by sweating (slippery hands, sweat in eyes, heated metal equipment) • May create perceptual difficulties (e.g., mirages, visual distortion, optical illusions) • Carrying heavy protective gear contributes to heat stress (gloves, boots, body armor)
Cold • Injuries associated with cold: Hypothermia, Immersion foot, Frostbite • Performance effects include: • Loss of psychomotor/manual dexterity, shivering • Reduced tactile sensitivity • Countermeasures: dry, layered clothing, warm food/liquids, wind barriers, large muscle activity
7000 m 5000 m 3000 m High Altitude • Altitude Sickness • Acute Organic Brain Syndromes – structural & functional defects in the CNS • Cyclothymic Syndrome – alternating depression, elevated mood • Paranoia, O-C, depression, hostility, decreased cognitive functioning • Neurasthenic Syndrome – fatigability, decreased motivation, psychosomatic symptoms + reduced visual ability • Loss of aerobic capacity by 10% for every 1000m over 1500 m
Noise & Hearing Loss Converts sound energy (outer ear) to mechanical energy (middle ear) to electrical nerve energy (inner ear), then sends signal to the brain
Decibel Scale Sound intensity (dB) = 20 log (P1/P2); where P2 is the threshold of hearing Note: M-16 rifle ~ 160 dB, M-198 Howitzer ~ 185 dB
Hearing Loss • Dangers of excessive noise: • Hearing loss – caused by exposure to loud noises. Some hearing loss is expected with age (higher freqs) • Loss of sensitivitywhile noise is present • Temporary Threshold Shift (TTS) – Loss of hearing that lingers after noise is terminated (post-rock concert) • - Tinnitus or ringing in the ears • - 100 dB for 100 min causes a 60 dB TTS • Permanent Threshold Shift (PTS)– Occupational Deafness caused by long term exposure (esp high freqs) • Eardrum rupture ~ 184 dB